The present invention relates to a fluorescent luminous tube and a fabricating method thereof, wherein the fluorescent luminous tube has anode electrodes and grid electrodes arranged in a matrix form, the grid electrodes being formed on insulating separators.
FIGS. 6A to 6C illustrate a graphic fluorescent display tube which is a type of prior art fluorescent luminous tubes, wherein FIG. 6A shows a plan view thereof; FIG. 6B, a cross-sectional view taken along a line xe2x80x9cY1xe2x80x94Y1xe2x80x9d of FIG. 6A; and FIG. 6C, an expanded view of a portion of FIG. 6B.
The prior art graphic fluorescent display tube includes an anode substrate 51 made of glass, filaments 61, each serving as a cathode, an anchor 62 for applying tension to the filaments 61, a supporting member 63 for supporting the filaments 61, an insulating layer 64, anode electrodes 71, fluorescent layers 72, separators 73 made of an insulating material, metal layers 74, and wire grid electrodes 75. The anode electrodes 71 and the wire grid electrodes 75 are arranged in a matrix form.
The fluorescent layers 72 of a dot array shape are disposed on the anode electrodes 71. The wire grid electrodes 75 are securely formed on the metal layers 74 disposed on the separators 73. Each of the separators 73 is formed to have a predetermined height by repeatedly printing an insulative paste on the anode electrodes 71 and, further, on the anode substrate 51 (between adjacent anode electrodes 71). See, e.g., Japanese Patent Laid-Open Publication No. 1990-123649.
In FIG. 6, the dots of the fluorescent layer 72 are precisely arranged on the anode electrode 71 with a predetermined size and interval and the separators 73 are actually aligned between adjacent fluorescent dots in a direction perpendicular to the length of the anode electrodes 71.
FIG. 7 illustrates a plan view of the anode substrate 51 to describe a case of misalignment of the separators 73. The filaments 61, the anchor 62, the supporting member 63, the metal layers 74, and the wire grid electrodes 75 are omitted therein for the sake of simplicity.
If the separators 73 are misaligned, for example, to positions 73xe2x80x2 shown in FIG. 7, each dot of the fluorescent layer 72 is partially buried thereby, so that a luminous area of the fluorescent layers 72 is reduced below a designed specification and the display quality is deteriorated. Accordingly, a printing mask used for forming the separators 73 should be very accurately aligned with respect to the fluorescent layers 72.
As previously explained, the separators 73 are formed by repeatedly printing the insulative paste to be sequentially laminated on the anode electrodes 71 and on the anode substrate 51 (between adjacent anode electrodes 71). Since, however, the insulative paste has a certain degree of fluidity, a first or a bottom paste layer of each separator 73 spreads over the anode electrodes 71 and the anode substrate 51, thereby generating a broadened portion 731 at the bottom thereof, as shown in FIG. 6C. Though the amount of spread depends on the paste employed, the broaden portion 731 normally enlarges a width of the separator 73 by about 50%.
Accordingly, a precise estimation of the size of the broadened portion 731 and an accurate alignment of the printing mask are needed in forming the separators 73. These requirements make it difficult to properly form the separators 73 and thus lower the yield of the fluorescent luminous tube. Therefore, a costly printing apparatus capable of performing a highly accurate alignment is required in forming the separators.
Furthermore, the broadened portion 731 makes it difficult to reduce an interval of the separators 73 because a large portion of the interval between adjacent separators 73 is wasted by the broadened portion 731; and therefor, the interval may be set with a greater design margin to prevent the dots of the fluorescent layer 72 from being buried thereby. For these reasons, it is very difficult to produce a high-resolution display by using a prior art fluorescent luminous tube.
It is, therefore, an object of the present invention to provide a fluorescent luminous tube, e.g., a fluorescent display tube and the like, and a method for production thereof, wherein the generation of broadened portions of separators can be avoided on fluorescent layers even when the separators are misaligned, thereby producing a high-resolution display.
In accordance with one aspect of the present invention, there is provided a fluorescent luminous device including: a substrate; a plurality of anode electrodes disposed directly on the substrate; fluorescent layers of a stripe pattern disposed on the anode electrodes; a multiplicity of separators disposed on the fluorescent layers and the substrate; grid electrodes respectively disposed on the separators, wherein the grid electrodes and the anode electrodes are arranged to form a matrix structure; and an electron-emitting source spaced apart from the fluorescent layers for exciting a fluorescent substance of the fluorescent layers.
In accordance with another aspect of the present invention, there is provided a fluorescent display device including: a substrate; a plurality of anode electrodes disposed directly on the substrate; an array of fluorescent dots disposed on the anode electrodes; a plurality of separators disposed on the fluorescent dots and the substrate, wherein at least a part of each of two neighboring separators is located on one fluorescent dot; grid electrodes respectively disposed on the separators, wherein the grid electrodes and the anode electrodes are arranged to form a matrix structure; and an electron-emitting source spaced apart from the fluorescent dots for exciting a fluorescent substance of the fluorescent dots.
In accordance with still another aspect of the present invention, there is provided a method for producing an anode substrate for use in a fluorescent luminous tube, including the steps of: forming anode electrodes directly on a bare anode substrate; forming fluorescent layers of a stripe pattern or a dot array pattern on the anode electrodes; forming separators on the fluorescent layers and exposed portions of the bare substrate such that the separators are arranged across the anode electrodes; forming grid electrodes on the separators to form a semifinished substrate; and baking the semifinished substrate.